Handle-operated electric motor starting switch



April 6, 1954 s. ALTER 2,674,672

HANDLE-OPERATED ELECTRIC MOTOR STARTING swITcH Filed on. 18, 1950 7Sheets-Sheet 1 an NJ #1 Inventor-:

xfl W m. y

Attorneys.

April 6, 1954 s. ALTER 2,674,672

HANDLE-OPERATED ELECTRIC MOTOR STARTING SWITCH Filed Oct. 18, 1950 7Sheets-Sheet 2 Inventor:-

J am, jmzzhmm wgl m Attorn eys.

S. ALTER April 6, 1954 HANDLE-OPERATED ELECTRIC MOTOR STARTING SWITCH '7Sheets-Sheet 3 Filed Oct. 18, 1950 Attorneys April 6, 1954 s, ALTER2,674,672

HANDLE-OPERATED ELECTRIC MOTOR STARTING SWITCH Filed Oct. 18, 1950 7Sheets-Sheet 4 a3 C P 9 9 PP". n

' i i I 4 h h] 7 I ,.lll| I a l| 1 h e3 I (QMETALQIQ) b 3 I: N ,5, 24 E:1 1. "lmlm lnventorz 3- awn. Ammwfiw gm,

Altorney April 6, 1954 ALTER I 2,674,672

HANDLE-OPERATED ELECTRIC MOTOR STARTING SWITCH Filed Oct. 18, 1950 7Sheets-Sheet 6 IO 15 F/G (BIMETALUC) Inventor:- CHILL,

Attorneys.

Patented Apr. 6, 1954 HANDLE-eOPERAT-ED ELECTRIC -MOTOR STARTING SWITCHSiegfried Altel-, Wa:lsall, England,--assignor to' LA. u Crabtree altGoQMmited, zwalsall, England; a

LBrItiShLcomPany- .Applicatlon'OctobenlS, 1950', ,Serial"No. 190,121

Clalins priority,- application Great Britain *March, 2 1950 21 Claims.1.

This invention relates to i dle operatedelectric.motor'cstartmgaswitches and is particularly concerned with single: or;multipole switches having a; relaydevice' in each pole.

for affording protection-to the motor gaga-inst overloads.

The principal objector the invention f. is to provid'euan improvedcompactuarrangement of small size; adaptedtto facilitate servicing andmaintenance, while being capable ofnsim-pleg production andpossessmgefiicient: electricah character-istics;

According to one t'eature of the invention; the

insulating base of -'the switch is partitioned soas to accommodate theterminals-contacts;and actuating "mechanism, in :a frontrchamberp andthe thermal- :overload devices :in :a rear chamber.

Thearrangement: enables the; bimetal elements of sueh thermal overloa'ddevicestosbe of. appropriately eflicient-lengtnwhile' preserving: thesmall. dimensions ofi'the switch; The :workingiparts of thegbimetals ofsaid thermaloverloadt devices; are preferably substantially straight.undeformed: strips with encircling heater. wires insulated from thebimetalsj ior example, :by looseinterposed mica plates.

Aceording: to a furthenfeature of i-the'i-invention, a catch;mechanismaisi interposed between.

a springpressed moving contactin-carrieriand the switch base for holdingthe switch aactuating:

means the on -:position, such catch mechanismriding rover anti'fri'ction: means, a, for ex ample a ball or roller, for ensuringsmooth-operatl'on.

According to another feature of the invention,

the insulating switchbase, 'iormed with com-- partments ior themountingvof' the fixed and moving contacts, is deeply: recessed' for th-reception of-:.-terminals, the headsf which I are therebyprotectivelydisposed well-to the rear' placement: ofsuch member, whichmember is disposed between the ends of such-ribs whendn the offposition, and has one endiprotrudingbeyondv suchuendswhen in: the 'fonposition, inorder to facilitate switching-off. The-arrangeimprovementsin: han' mentealso contributes tothe rellableoperation of the switch inpositions in which it is difllcult: to seeithecswitch, therebyminimising the risk. of errors' inoperation.- 'The handle. on which the'slider. is mounted with. a degre .oi lost-motion, may-,be pivotalwith-respectto the slider, inrsuch manner :that after an initial angularmovement for nomnallyeiiecting a breaking of thecontacts. afurtherangular "movement is. efiective: for positively disengaging thecontacts. Thus= thesaham' dletprovides a quickrbreak :of. the:contactsaand ensures a positive drive; in both directions. v.Inv steadofbeing connected with asl-ider, the r-handle may: be operated bylinkageror the like.

In -order toenable the, inventiontobe: readily understood, referencewill, now rbegimade :to: the accompanying drawings illustrating .by wayof example, one construction 1" of three-pole manwally operated:starting, switch having a: thermal overload release device in each pole,in which drawings:

,Eigure 1- is a frontelevation with-parts inrsec tion.

Figure 2 is a front elevation-with the :front cover removedand showingthe front contact chamber.

: Eigu-re3 isa side elevation.

Eigure 4-. is. a sectionon the line-IV-IV of -Figurea-2, withthe parts:of thercovenshown in ele vation.

Figure 5 is-a section on. the: line .VVofz Fig ure 6.

Figure 6 is'arear elevationwith thezback plate removed .to disclose theoverload' chamber.

,Figureflhisaa section on: the line VIP-VII: of Figure. 2,. withsthefront cover in position.

.FigureB isa section on the line-VIII-VIII of igure 7..

'Figure'9 is a view similar to Figure. 7 but showing the clutch plateand associated parts innthe off position.

Figure I0 is an elevation of the end. plate and the partsmounte'dthereon,-including the stressed blade" and catch p1ate',"removed fromthe switch, theambient and its mounting being also shown inthi's'figure';

Figure 11 is'a'rearview of the slidablehandle.

.Referring to the drawings, ablock or based ofzinsulatingmaterial hasfrontand rear chem-- bers separated by a'middle wall a (see'F'igures 7andzzQ); the .rf-ront chamber being formed with partitionsfxto providethree' -to'p and'bottomcompartmentssbueach adapted for the reception ofalterminali cc and-waxed contact d (see "Figure 2):,iwhilerthe;rearchamber-is formed with provided for receiving the trip mechanism. An

insulating moving contact carrier e (see Figure 2) is slidablehorizontally between theupper and lower compartments b in order toeffect engagement or disengagement of contactjplates e thereon with thefixed contacts d. The terminals co may be disposed in deep recesses g,Figure 4,

so that their screw heads, which are disposed well to the rear of thesurface front'of the base, are

not liable to be inadvertently touched. 3

The side walls of the base are formed with channels or openings 10 (seeFigure 4) .to enable cables to be introduced laterally under clamps, thescrews being tightened to secure the conductors in position. The pillarof the upper terminal 0 extends through the wall a (see Figure 4)separating the front and rear chambers, and its rear end is connected bya screw g 'to the upper end of a heater wire it which is coiled around,and is welded at its other end to a bimetallic strip 1' disposed in acompartment is in the rear chamber. The upper end of the bimetal isconnected by a screw Z to a strap m extending through an opening in thewall a of the base, the forward end of the strap being connected by ascrew n to one of the fixed contacts d, the outer end of the other fixedcontact d being screw-connected to a strap 0 disposed in a recess in thefront chamber and riveted to the other terminal 0 Each of the fixedcontacts d is in the form of a looped resilient blade having a silvercontact d at its inner end, the looped formation enabling it to bepre-stressed so that it presses against a stop formation a of the base,in the off position. As a result, when operated to the "on position,each moving contact e encounters a pressure immediately upon contactengagement.

Each bimetal strip 1' is separated from its heater coil h by a pair offiat elongated mica plates h which are engaged at their upper ends byribs e of the casing and at their lower ends by a centralising rivet hentering locating slots b in the mica plates. the possibility of shortcircuit between a heater coil and its strap m. The mica shields, whichare wider than the bimetal, are loose so as not to interfere with thebending of the bimetal. Only a low watt input is necessary for obtainingadequate movement of the bimetal, because the latter is not required toeffect bending movement of the insulating means as in the case of asleeve or plates tightly enclosing or surrounding the bimetal.

The silver buttons d on the inwardly .directed ends of each pair offixed contacts are adapted to be bridged by the co-operating silverbuttons e on the inner ends of U-shaped moving contact plates e on theinsulating carrier e. The connecting limb of each Ushaped.plate islocated in a groove on the rear surface of the carrier and its arms inupper and lower grooves e therein. The grooves of each pair are ofdifferent lengths and the inner surfaces of the arms of each movingcontact are correspondingly formed (see Figure 4) to ensure correctassemblage of the contacts on-the carrier." These arms extend above andbelow the carrier so that the 4 buttons :2 thereon are enabled to engagewith the buttons d of the fixed contacts.

One end of the carrier e is of channel section for receiving a clutchmechanism, Figures '7 and 9, which clutch mechanism includes a two-armedlever t. The other end of carrier e is of socket-- like shape for thereception of a helical comiii pression spring 1 which acts between thebase a and a partition e of the carrier for urging the carrierrightwards (Figure 2), in order to disengage the contacts. The carrier,which may be moved leftwards against the action of the spring 1' bymeans of a stud s, actuated as hereinafter described, is retained in theon position, with the contacts engaged, by means of the two-armed levert of the clutch mechanism which, in effect,

, constitutes a catch plate or coupling. Lever t,

The ribs e also prevent a,

as best shown in Figure 10, is formed with lateral wings t having lugst? which enable it to be pivoted on the plate 3, and with ears h whichproject into apertures 3 in the plate. -Arms 3 bent downfrom a bracketformation 3 on the plate, retain the ears in the apertures with thelever held in position on the plate.

The lever arm t extending into the carrier, is flanged, and to thisflange is secured, by a rivet t", a hardened L-shaped metal plate t*.The inner end if of this plate is of arcuate shape having its centre atthe pivotal point of the lever on the plate 3, that is, at the pointwhere the wings t are pivoted on the plate 3. The other arm 1. of thelever is engaged by the depending leg u-' of the spring u whichinfluences the lever to the position Figure '7, for retaining thecarrier e in the 0 "position.

The shaped end t of the plate t and the extremity of the lever arm t areadapted for engagement with a ball or roller 0 disposed in a horizontalguide 12 near the right end of the carrier. An L-shaped metal bracket wis slidably secured in the carrier e by means of a blank l and it isslidable against the action of a hellcal compression spring a: disposedbetween a short arm w of the bracket and this blank, which abuts againsta wall 11 of the carrier. The extremity of the longer arm is formed as aramp 10 for engagement with an edge t of the catch plate to enable thelatter to be disengaged from its locking engagement with the ball 12.This longer arm is disposed in a different plane from that of the plate1.", so that the bracket can move relatively to the lever withoutbearing on the latter.

For convenience in assembly, the blank l is in the from of a T-shapedmember the leg of which is introduced to one side of the spring atand-its extremity l is then bent, as seen in Figure 9, by a suitabletool for holding the bracket 10 in position in the carrier. An extendedarm 10 of this bracket also serves to restrict the forward movement orthe ball 12.

The stud s for operating the moving "contact carrier e extendsrearwardly from a plate 4 pivotally mounted at its lower end by a rivet5 ona plate Bsecured to the base a by means of screws 1, which screwsengage in tapped openings in the bracket portion 3 of the plate 3. Arearward U-shaped side 6 of this plate embraces a projection a of thebase for retaining the plate in position thereon. At the cornerconnection of these sides with the plate 6 a degree of flexibility isprovided to enable the plate to be clipped in positon while taking upproduction tolerances. The plate Sis formed with two raised lateral earss 'into tappings' in which are introduced screws angersi'xlfor:securingacoverplatei i l -imposition there:-

on; The-stud s, which' -is riveted to the pivotal plate midway betweenits ends and extends through an arcuateslot fi in the 'fi-xed plate 6;-is influenced to occupy aposition at the'rightwards end of i this slotby=means of thespring T which acts-on the carrier e,'--this =end of 1the slot being enlarged -to enablethe introduction of an enlargedcollars which has flanged guiding engagement 'with theedgesv of the narrowpart of the slot.

An insulating slider l0, iHFfiFig-ure 11, isgui'dlnglymovablebetweenupper and -lower ribs l4, H, which may be die castings, secured by-screws W to the cover H; and a helical spring ['6 isoperativebetweenthe'lowerrib H and the slider-"for normally returning the latter to --aposition 1 in which its ends coincide with" the ends-of the ribs asshown in Figure 1. This corresponds to the oil? position ofthe-switchand it -is-only'= in this position'thatbcth securing screws Ffor the'cover areexposed. The ribs, which-are" formed with locatingstuds [4 entering holes in the cover'll, act protectively-forpreventinginadvertent actuation of the slider, operation of which requiresendwise' pressure so-that one end is displaced beyond'the ribs forswitching on. The-ribs maybe readily removed to'enable'the indicationplate-13 to bereversedor-bhanged. The slider parts- I 0,' Hi separatedby athin metal strip l 5 may be'disti-nctivelycoloured, for examplegreen and 'red, 'for indicating which end 'shouldbe pressed to ensurethe desired operation of the switch and they are secured by screws ll,Figure 11', to a metal plate Hi having lugs' lfl for'slidably retainingthe'parts between the ribs. The plate I 0 slides on a thinsheet 13 ofinsulating material which bears a "legend such as on',?' which isdisclosed in theappropriate'position of the handle. Extending from 'theupper end of the pivotal plate is a pin 8' on the" forward end of whichis'a roller-"9' which isdispose'dl in the recess 8 formed between theparts I0, us

In operation; movement of the slider NI; His, leitwards to the"onposition,' againstxthe action of the handle spring i6, causes themovement of the carrier e to engage the moving contacts 6 with 'theircomplementary fixed contacts d The plate t secured to the catchplaterides over the ball-v until, inthe engaged position of the contacts; thepressure of" the spring u causes the shaped end i to be pressedrearwards into: look-- ing engagementwith the-b'allfor preventingreturn"of"the'carriene. "Thus the plate t acts. as an abutmentformaintaining the carrier insthe on position until the handle isoperatedtathe oif position. When'this' takes place the stud s moves theL-shaped "member w rightwards, against 'theaction' of the spring nuntilthe ramp orincline w thereof encounters theedge. t of the catch plateand causes it to' be. turned T forwards and disengaged from its lockingengagement with the ball. Thereupon the carrier spring 1' is enabled.tomove the carrier and disengage the contacts. .During this. operationthe ball moves in. its guide andlthe frictionalengagement between itandthe. catch tooothl is thereby reduced-to a. minimum.

The rectangular plate: 3:: has, securedv to its: inner. surface, ,a.blade [9,. Figure 10, which .is stressed by'a spring-2B2 soaas to moveaway from the,- plate, andrwhich isr'adapted for. engagementwith;therearwarclly:extendinguirm"t of 'the catch plate. The-blade-isnormally restraihedirom-ewerting pressure on such arm by mea-nslotanamrivet/s22- an insulating arm, three lateral extensions 24 of which,are adapted to be engaged by the ends-of the bimetal elements 1'. Duringoverload conditions, the bending of the bimetal 12 acts on the trip bar24' to cause the pivoting of the metal bar 23-, against the action ofhelical springs 25 each of which acts between the bar; anda-stud 26carried by the base, for normally pressing the bar against stopformations 21 of the: base. The upper end ofeach extension 24 isprovidedwith an adjustable screw 28 which enablesindividual adjustment of anextension in relation to itscooperating bimetal. The metal bar 23 isformed with ends 23 which enter recesses 23 in the base to providepivotmountings. Pivoting of the bar 23 causes rearwardmovement of theambient so as to remove it from obstructive engagement with the stressedblade IS'which isthen free to turn outwards away'from the rectangularmetal plate 3 and impinge-on the leg't ofthe catch' plate which-isturned to theposition show-nin Figure 9, and disengaged from its lockedengage ment with the ball 12' of thecarrier e, which'c an then be movedby the spring r to carry themoving contacts c to the on position, asseen-in chain lines in Figure 2.

Rightwardly projecting noses e on the moving contact carrier are adaptedto engage the stressed blade iii to press it towards the plate-3 andthis'enables the catch plate tore-engagetheball '0 when the handle isoperated. A lateral flag-like extension li on the ambienten sures thatthe latter is always-re'-engaged"on the appropriate side of-thestressedblade Hi. When the switch is on, the ball 22 is disposed tothe rear ofthe dead center position, of the lever" t, so as to avoid thepossibility of inadvertent operation to cause tripping. The arrangementnecessitates-a relatively powerful force to effect tripping, but this isproduced with a relatively light action of the bimetals-owing to themechanical-advantage with which the bar acts on the ambient.'Moreoverthe' presence of the gap between the stressed plate l9 and thelegt ensures that the former impinges on the leg i with an impact orblow so that a correspondingly small force is required for operation 'bythe bimetal. I

The stressed spring blade H) can be turned about-apivot 29 at its uppercorner for adjustment purposes thereby requiring a 'greater'or lessermovement of thebimetals, andthe' ambient, to efiect tripping of theswitch. One position of adjustment is shown in chain lines in Figure-10. The degree of adjustment maybe measured on a scale" 3ll-on a. labelplate 3|, Figure 3',-whichis' attached to the plate 3' and which isformed with a bulge 32- to accommodate the ears t of the catch-plate.coinciding holesin the label and the plate 3 enable the introductionofmeans for operation of the catch plate t, if desired, by; remote controlmeans.

The'stressed-blade l9-is adjustable about its pivot 29-bymeans of apointer 34, the pointed end of'which co-operates with 'thescale and theother end of which is mounted on a rotatable bush 35 pivoted in therectangular plate and having a pin "36* which is" eccentric in the. bushand which is movable in" aslot 31 in the blade. The pointer-and the bushare'individually adjustable. For-adjustment a screw'Ml is first loosenedand the bushand pointer maybe" turned 7 in the arcuate slot 40, thescrew then being tightened for securing the parts in position. Thepointer 34 is formed with a bead 34 which is slotted at 34 between itsends, and this arrangement facilitates adjustment either by hand or by ascrew driver. A leg 11. of the spring u enables any slack around thepivot 29 to be taken up. Two wings 38 on the pointer are slightly bentso as to exert pressure on the plate and enable it to be frictionallyretained in positions of adjust- 1 ment, and these wings abut againstthe label plate in respective extreme positions and thereby restrict theangular movement of the pointer.

The cover of the sheet metal box, which is provided with suitableconduit entries, is adapted to be removed only when the switch is in theoff position.

Having thus described my invention I claim:

1. A handle-operated electric motor starting switch comprising aninsulated base chambered and partitioned and having walls defining afront chamber, a rear chamber, and an end chamber in said base; pairs offixed contacts in said front chamber; a carrier in said front chamberslidable between opposite pairs of said fixed contacts; transversemoving contacts mounted on said carrier for engagement with said fixedcontacts; thermal relay devices disposed in said rear chamber; manuallyoperable means for said carrier mounted on the wall defining the frontof said front chamber; and means mounted in said end chamber andcontrolled by said thermal relay devices for automatically tripping saidcarrier and comprising a catch mechanism adapted to be released by saidthermal relay devices upon overload conditions. I

2. A handle-operated electric motor starting switch comprising aninsulated base chambered and partitioned and having walls defining afront chamber, a rear chamber, and an end chamber in said base; pairs offixed contacts in said front chamber; a carrier in said front chamberslidable between opposite pairs of said fixed contacts; transversemoving contacts mounted on said carrier for engagement with said fixedcontacts; thermal relay devices mounted in said rear chamber and eachincluding a strip-like bimetal element; manually operable means for saidcarrier for controlling the position of the contacts thereon withrespect to said fixed contacts; means mounted in said end chamber andcontrolled by said thermal relay devices for automatically tripping saidcarrier and comprising a catch mechanism adapted to be released by saidthermal relay devices upon overload conditions, the plane of movement ofthe moving contacts being parallel to the plane of the bimetal elementsin said rear chamber and to the partitions which separate said front andrear chambers.

. 3. Ahandle-operated electric motor starting switch comprising aninsulating base having a partition to define front and rear chambers insaid base; a bimetal overload release device mounted in said rearchamber and including a straight bimetal element; a common releasablecatch mechanism operated by said bimetal overload release device; amanually operable device for actuating said catch mechanism; and fixedand movable contacts mounted in said front chamber, the plane ofmovement of said movable contacts being parallel to said partition andto the plane of said bimetal element.

4. A handle-operated electric motor starting switch comprising manualoperating means; a trip mechanism; a thermal overload release sin deviceincluding a straight bimetal element operable on said trip mechanism torelease the same to open contact position; pairs of fixed contacts; aslidable carrier movable between opposite pairs of said fixed contacts;spaced contact plates on said carrier for engagement with said pairs offixed contacts; and a catch mechanism operated on by said thermaloverload release device upon overload conditions and comprising aright-angled lever, one arm of which is actuated by said trip mehcanism,and the other arm of which is disposed in line with said slidablecarrier and is actuated by said manual operating means.

5. A handle-operated electric motor starting switch comprising manualoperating means; a trip mechanism; a thermal overload release deviceincluding a straight bimetal element operable on said trip mechanism torelease the same to open contact position; pairs of fixed contacts; aslidable carrier movable between opposite pairs of said fixed contacts;spaced contact plates on said carrier for engagement with said pairs offixed contacts; a catch mechanism operated on by said thermal overloadrelease device upon overload conditions and engageable with said carrierfor retaining the contact plates thereon in engagement with said pairsor fixed contacts; and antifriction means interposed between saidcarrier and said catch mechanism, said trip mechanism being actuated bysaid thermal overload release device upon overload conditions and be-,ing operable on said catch mechanism for releasing said carrier.

6. A handle-operated electric motor starting switch comprising aninsulating base having partitions and walls to define front, rear, andend chambers, said end chamber extending from the front to the rear ofsaid base; fixed contacts disposed in pairs in said front chamber; acarrier in said front chamber movable between op posite pairs of saidfixed contacts; contact plates on said carrier for engagement with saidfixed contacts; overload release devices in said rear chamber and eachincluding a straight bimetal element disposed in a plane parallel to thedirection of movement of the carrier in said front chamber; a catchmechanism mounted in said end chamber and including a two-armed lever,one .arm of which is disposed substantially in line with said carrier,and the other arm of which is disposed substantially in line with saidend chamber and is adapted to be tripped by the overload release devicesupon overload conditions for releasing said catch mechanism; andmanually operated means on the front wall defining said front chamberfor actuating said carrier.

7. An electric motor starting switch having a handle for operation ofthe switch to the on" and off positions thereof; pairs of fixedcontacts; a carrier movable between said pairs of fixed contacts andhaving spaced contacts thereon for engagement with said fixed contacts;a thermal overload release device for said carrier; a spring operativeon said carrier to disengage the contacts thereon from said fixedcontacts; a pivotally mounted catch lever engageable with said carrierand adapted to hold said carrier in the on position of said fixed andmovable contacts against the action of said spring; trip mechanism forsaid catch lever actuated by said thermal overload release device andoperative on said catch lever to permit said spring to move said carrierto the off position of said fixed and movable contacts; and antifrictionmeans emon interposediibetween said leverrand said carrier.

8. .An :electric :motor starting: switch having; a handleforwoperationwof the switchrto the on" and ed positions thereoff;pairswof fixedzcontacts a: carrier movable between 1 said; pairs offixed contactsand having spacedscontacts 17118178.- on for engagementwith said, fixeducontacts; a thermal overload release device.fOI"$&idFCM1'-i8l.', said carrier being, so formed-as to. providerschannel section: at ione'end thereof; a catchalever operable on saidcarrier and positionediaduacent the channeled: end; thereof; 1antifriction means disposed between the: channeled end: of zeaidrcarrierand said catch lever; :the other: endz-ofrsaid carrier havingsa socket.thereini; 'a..ihelioalacom;- pression spring disposed in said socketand operativei on said carrier for-urging s it to a position fordisengaging sthe contacts'on:saidz;ca-rrier from said fixed contacts; ahandle for moving said carrier to cause engageznentofsaid fixed'andmovable contacts; and trip means for said..1cat'ch lever operate'd-bytheoverload .Jrelease device for releasing said -catchmechanism .topermitsaid spring to move-thecontactsonsaid carrier out of engagementwith said fixed contacts.

9. An electric motor starting switch in accordance with claim 8, inwhich the movable contact carrier is provided with projectionsengageable with a stressed blade for enabling the ,catch lever toreengage the antifriction means when the handle is moved to bring thecontacts on the carrier into engagement with the fixed contacts after atripping operation of the switch by the overload release device.

10. An electric motor starting switch in accordance with claim 8,including a pivotally mounted stressed blade and a spring, one leg ofwhich spring is adapted for influencing the catch lever to its onposition, and another leg of which is operable for taking up slack inthe position of the stressed blade about its pivotal mounting.

11. An electric motor starting switch in accordance with claim 8,including a scale and a pointer cooperating with said scale, saidpointer being pivotally mounted on a rotatable bush, and said bush andsaid pointer being individually adjustable to vary the relationshipbetween said scale and pointer.

12. A handle-operated motor starting switch in accordance with claim 11including a fixed plate having an arcuate slot therein, a pivotallymounted plate having a stud extending therefrom for operating themovable carrier, a pin on said pivotally mounted plate and on which is aroller engageable with the handle which operates the movable carrier,said pin extending through the arcuate slot in the fixed plate, and aspring for influencing said pin to occupy a position at one end of saidarcuate slot.

13. An electric motor starting switch in accordance with claim 8 andcomprising a handleoperated plate mounted on the carrier and formed witha ramp which is engageable with said catch lever for moving it to the01f position.

14. An electric motor starting switch having a handle for operation ofthe switch to the on and off positions thereof; pairs of fixed contacts;a carrier movable between said pairs of fixed contacts and having spacedcontacts thereon for engagement with said fixed contacts; a thermaloverload release device for said carrier; said carrier being so formedas to provide a channel section at one end thereof; a catch leveroperable on saidrcarrier and: positioned adjacent the: channeled endthereof; antifriction means disposedsbetween the channeled end of saidcar.- rier-andtsaid-catch :lever; the other end of said carrierrhavin'grassocket' therein; a helical cornpression {SDIiI'lE'Tdl'SIJOSBdiiD'saidsocket; and operative on said carrier for urging it tov aaposition.for disengaging the contacts on :said carrierfrom saidfixed' contacts; ahandle for moving said vcarrierr'torcause engagement of said fixed and.movablez contacts; tripimeans operated by the overloadwrelease devicefor releasing said catch lever: astressedEbladeadapted to impinge uponsaidi'tcatchtdever; aotrip bar actuated by said thermal overload releasedevice; and an ambient temperature rco-mpensating'arm secured to saidtrip: -'bar:':an;dadapted: to prevent said. stressed bladefrom'zimpingin'g 31113011 said catch lever.

153111121, handle-:operated:electric motor starting, zswitchvhavinguarr.overloadzrelease device for saidiswitch, afrontplateihavingtupper andlower ribs .thereon', -a..movingr contact :carrier, atransvers'ely'rsli'ding handieaoperably connected with saidf'carrier; for :operating.said switch. to .oiT and on positions and slidable between the ribs onsaid front plate, said transversely sliding handle being disposed andrelated to said ribs in such manner that said handle is disposed betweenthe ends of said ribs when said switch is in the off position and hasone end protruding beyond said ends of said ribs when said switch is inthe "on position.

16. A handle-operated electric motor starting switch having a thermaloverload release device, and comprising an insulating switch basechambered and partitioned and having walls defining a front chamber, arear chamber, and an end chamber, pairs of fixed contacts in said frontchamber, a carrier in said front chamber slidable between opposite pairsof said fixed contacts, transverse moving contacts on said carrier forengagement with said fixed contacts, straight bimetal elements disposedin said rear chamber in a plane parallel to the plane of movement ofsaid carrier, catch mechanism mounted in said end chamber engageablewith said carrier and adapted to be tripped by the bimetal elements insaid rear chamber upon the occurrence of overload conditions, and ahandle on the wall defining the front of said front chamber for manualactuation of said carrier.

17. A handle-operated electric motor starting switch in accordance withclaim 16, in which the switch base is formed with compartments for themounting therein of saidfixed and said transverse moving contacts and isdeeply recessed for the reception of terminals, the heads of whichterminals are protectively disposed well within the surface of the base,said base having channels formed in the walls thereof for the passage ofconductors to the terminals.

18. A handle-operated electric motor starting switch in accordance withclaim 16, in which the thermal overload release device includes a heatercoil having one end connected to a terminal and its other end connectedto one of the bimetal elements, and a trip bar for said catch mechanismadapted for actuation by said bimetal element and having individualadjustment for equalizing the gap between said trip bar and said bimetalelement, the end of said bimetal element to which said one end of saidheater coil is com nected being adapted to impinge upon said trip bar.

19. A handle-operated electric motor starting switch in accordance withclaim 18, in which there is a stop on the insulating switch base, and inwhich the trip bar is of L-section having lateral extensions thereonprovided with adjustable screws and springs for returning said trip barto a normal position against the stop on said insulating base.

20. A handle-operated electric motor starting switch in accordance withclaim 18 in which each bimetal element is straight and is separated fromand surrounded by a heater coil, said bimetai element being separatedfrom the surrounding heater coil by loose individual interposed micaplates, one disposed on each side of said straight bimetal.

21. A handle-operated electric motor starting switch including a thermalrelay device for atfording protection to the motor against overloads andcomprising a switch base of insulating material chambered andpartitioned and having walls defining a front chamber, a rear chamber,and an end chamber; terminals, fixed, and movable contacts positioned insaid front chamber; thermal overload relay devices positioned nected toaterminal and the other end of said heater coil being connected to abimetal, the end of said bimetal to which said one end of said heatercoil is connected being adapted to impinge upon said trip bar, and saidtrip bar being adjustable for equalizing the gap between said lastmentioned end and said bimetal.

References Cited in the file of this patent I UNITED STATES PATENTSNumber Name Date 1,980,487 Werner Nov. 13, 1934 2,342,945 Krieger Feb.29, 1944 2,482,009 Link Sept. 13, 1949 2,496,072 Taylor Jan. 31, 1950

